In a lab build I'm doing, I'm stuck at this problem, so I am fishing for suggestions.
I'm creating a turn-table type setup where I need to make readings (with a nanotube-tip probe I've already designed, similar to an AFM probe) on the very edge/circumference of a 10 cm radius disk (substrate).
The current hurdle is: I need to get the substrate disk to move circularly in steps of 0.1 mm displacement -- meaning, I occasionally need to STOP at certain 0.1mm-increment positions.
What would be a way I can achieve this, assuming an accurate feedback system (with accuracy of say ~0.1 mm, e.g., with quadrature optical encoders) is available if needed for closed-loop control?
Specs of commonly sold steppers don't seem to allow this kind of control. I'm at the moment trying to study how, e.g. hard disks achieve extreme accuracies (granted they don't have such large disks).
Certainly, direct-drive like I'm currently building (see below image) probably doesn't help!